Memory devices may be employed in various electronic devices, such as computers, cell phones, PDA's, data loggers, and/or navigational equipment, just to name a few examples. For example, various types of nonvolatile memory devices may be employed, such as solid state drives (SSD), NAND or NOR flash memory, or phase change memory, among others. In general, writing or programming operations may be used to store information, while read operations may be used to retrieve stored information.
Phase change memory (PCM) may operate based, at least in part, on behavior or properties of one or more particular phase change materials, such as chalcogenide glass or germanium antimony telluride (GST), just to name a few examples. Electrical resistivities of crystalline or amorphous states of such materials may be different from one another, thus presenting a basis for distinguishing information states. For example, an amorphous, high resistance state may represent a stored first binary state and a crystalline, low resistance state may represent a stored second binary state. Of course, such a binary representation of stored information is merely an example: Phase change memory may also be used to store multiple memory states, represented by varying degrees of phase change material resistivity, for example.
Non-volatile memory may involve asymmetrical latencies between storing data of ‘1’ and ‘0’ due to technology limitations and/or intentional design of such memory. For example, a PCM device may take longer to store a one-bit (if a one-bit represents a relatively low resistance, crystalline state) than to store a zero-bit (if a zero-bit represents a relatively high resistance, amorphous state). Also, within a given system, from the same memory, some applications may involve faster storage of one-bits while other applications may involve faster storage of zero-bits.